ERP denoising in multichannel EEG data using contrasts between signal and noise subspaces

In this paper, a new method intended for ERP denoising in multichannel EEG data is discussed. The denoising is done by separating ERP/noise subspaces in multidimensional EEG data by a linear transformation and the following dimension reduction by ignoring noise components during inverse transformation. The separation matrix is found based on the assumption that ERP sources are deterministic for all repetitions of the same type of stimulus within the experiment, while the other noise sources do not obey the determinancy property. A detailed derivation of the technique is given together with the analysis of the results of its application to a real high-density EEG data set. The interpretation of the results and the performance of the proposed method under conditions, when the basic assumptions are violated – e.g. the problem is underdetermined – are also discussed.Moreover, we study how the factors of the number of channels and trials used by the method influence the effectiveness of ERP/noise subspaces separation. In addition, we explore also the impact of different data resampling strategies on the performance of the considered algorithm. The results can help in determining the optimal parameters of the equipment/methods used to elicit and reliably estimate ERPs.     

The patient-therapist interaction and the recognition of affects during the process of psychodynamic psychotherapy for depression

The perceptions of patients (n = 25) and their therapists about psychodynamic psychotherapy for depression were assessed during the first treatment year using 23 scales. Patients and therapists independently evaluated the impact of depression on the therapeutic experience of the patients. The estimations of the impact of depression by the patients and therapists were concordant in the majority of the subjects, reflecting mutual tuning and a working alliance. The roles of affects and frustrating subjects in the treatment relationship were evaluated as significantly different by the patients and the therapists. The results highlight the importance of working on the expression of affects in the psychotherapy of depression.     

Comparison of Oral Anticoagulants for Stroke Prevention in Nonvalvular Atrial Fibrillation: A Multicriteria Decision Analysis

Background

Decision on the most appropriate oral anticoagulation therapy for stroke prevention in patients with nonvalvular atrial fibrillation is difficult because multiple treatment options are available, and these vary in their clinical effects and relevant nonclinical characteristics.

Resting Electrocardiogram and Blood Pressure in Young Endurance and Nonendurance Athletes and Nonathletes

ContextMuch information is available on electrocardiogram (ECG) and blood pressure (BP) changes in senior athletes. However, corresponding data on adolescent athletes are scarce.ObjectiveTo study the differences in resting ECG and BP values among adolescent endurance athletes, nonendurance athletes, and nonathletes.DesignCross-sectional study.SettingA total of 154 youth sports clubs in Finland and 100 secondary schools for comparison data.Patients or Other ParticipantsWe recruited young athletes (n = 410) aged 14 to 16 years in 10 popular sport disciplines, including winter and summer as well as team and individual sports, and categorized them as endurance or nonendurance sports. Comparison data for age-matched, non–sports club participants (n = 164) were collected via secondary schools.Main Outcome Measure(s)Resting ECG, including heart rate, PR interval, QRS duration, QRS axis, QRS amplitude, T axis, and QT interval as well as systolic and diastolic BPs.ResultsNo differences in any ECG variable of interest were found between the endurance and nonendurance athletes. The PR interval was longer in endurance athletes than in nonathletes (P = .05). The QRS amplitude (P = .03) was higher among nonendurance athletes than among nonathletes. Diastolic BP was lower among endurance (P = .002) and nonendurance (P = .02) athletes than among nonathletes. Endurance athletes (odds ratio [OR] = 2.85; 95% CI = 1.81, 4.50) and nonendurance athletes (OR = 2.19; 95% CI = 1.43, 3.35) were more likely to have sinus bradycardia than were nonathletes. Nonendurance athletes were more likely to have elevated systolic BP than were endurance athletes (OR = 1.70; 95% CI = 1.07, 2.72) and nonathletes (OR = 1.73; 95% CI = 1.04, 2.87).ConclusionsYoung athletes had similar ECG and BP findings independent of their sports. Physiological adaptations including sinus bradycardia, higher QRS amplitude, and lower diastolic BP, which are commonly seen in adult athletes, were also present in adolescent athletes.     

High indoor CO2 concentrations in an office environment increases the transcutaneous CO2 level and sleepiness during cognitive work

The purpose of this study is to perform a multiparametric analysis on the environmental factors, the physiological stress reactions in the body, the measured alertness, and the subjective symptoms during simulated office work. Volunteer male subjects were monitored during three 4-hr work meetings in an office room, both in a ventilated and a non-ventilated environment. The environmental parameters measured included CO₂, temperature, and relative humidity. The physiological test battery consisted of measuring autonomic nervous system functions, salivary stress hormones, blood's CO₂- content and oxygen saturation, skin temperatures, thermal sensations, vigilance, and sleepiness. The study shows that we can see physiological changes caused by high CO₂ concentration. The findings support the view that low or moderate level increases in concentration of CO₂ in indoor air might cause elevation in the blood's transcutaneously assessed CO₂. The observed findings are higher CO₂ concentrations in tissues, changes in heart rate variation, and an increase of peripheral blood circulation during exposure to elevated CO₂ concentration. The subjective parameters and symptoms support the physiological findings. This study shows that a high concentration of CO₂ in indoor air seem to be one parameter causing physiological effects, which can decrease the facility user's functional ability. The correct amount of ventilation with relation to the number of people using the facility, functional air distribution, and regular breaks can counteract the decrease in functional ability. The findings of the study suggest that merely increasing ventilation is not necessarily a rational solution from a technical-economical viewpoint. Instead or in addition, more comprehensive, anthropocentric planning of space is needed as well as instructions and new kinds of reference values for the design and realization of office environments.     

Endothelial L-selectin ligands in sinus mucosa during chronic maxillary rhinosinusitis

RATIONALE: Chronic rhinosinusitis is characterized by persistent inflammation of the nasal and paranasal mucosa with numerous emigrated leukocytes. L-selectin on leukocytes and its endothelial glycosylated ligands initiate organ-specific leukocyte infiltration into inflamed tissues. OBJECTIVES: The purpose of this study was to evaluate the endothelial expression of functionally active endothelial L-selectin ligands, sulfated sialyl Lewis x, in maxillary sinus mucosa from patients with chronic rhinosinusitis and from normal control subjects. METHODS: Maxillary sinus mucosa specimens (116) were obtained surgically and immunohistochemically stained with monoclonal antibodies detecting sialyl Lewis x or sulfated extended core 1 lactosamines. The severity of the inflammation was determined by intraoperative endoscopic findings, computed tomography scans, and histopathologic assessment of the specimens. MEASUREMENTS AND MAIN RESULTS: The percentage of vessels expressing endothelial sulfated sialyl Lewis x epitopes increased during chronic rhinosinusitis compared with uninflamed control tissue, especially in patients with additional allergic rhinitis, and decreased in specimens from aspirin-intolerant patients with preoperative oral corticosteroid treatment. In addition, the expression level of endothelial sulfated sialyl Lewis x epitopes and the number of mucosal eosinophils correlated with the severity of the inflammation, and decreased in specimens taken 9 months postoperatively compared with intraoperative samples, especially in patients with intranasal corticosteroid treatment. CONCLUSIONS: Our results suggest that functionally active L-selectin ligands might guide leukocyte traffic into maxillary sinus mucosa preferentially in patients with severe findings of chronic maxillary rhinosinusitis, thus leading to aggravation of the inflammation.     

Ethanol inhibits alpha-amino-3-hydyroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor function in central nervous system neurons by stabilizing desensitization

Ethanol actions on alpha-amino-3-hydyroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors were studied using voltage-clamp recordings from mouse cortical and hippocampal neurons. During whole-cell recordings ethanol (EtOH) inhibited AMPA receptor-mediated currents in a dose-dependent manner at concentrations from 10 to 500 mM. The steady-state component of AMPA-activated current was more sensitive to EtOH than the peak component. To examine the effect of EtOH on a well resolved peak current component, patches were excised from cultured cortical neurons, to which AMPA and EtOH were applied using a piezoelectric solution application system. Under this condition, the peak current was not inhibited significantly by EtOH. To further study possible mechanisms of EtOH inhibition, kainate and AMPA were used to evoke currents in the absence and presence of cyclothiazide. Ethanol inhibition was stronger when receptors were activated by low than high kainate concentrations. Cyclothiazide reduced inhibition by EtOH regardless of the agonist used to activate the receptor. Finally, EtOH inhibition was reduced in a point mutated (L497Y) GluRAi receptor that lacks desensitization. These findings suggest that EtOH inhibits AMPA receptors by stabilizing the desensitized state. Our results can explain some of the variation observed in EtOH inhibition in previous studies, and support the idea that physiologically relevant concentrations of EtOH can have a strong effect on AMPA receptor function.     

Risk factors for developing tuberculosis in remand prisons in St. Petersburg,Russia — a case-control study

Background Detainees have a substantial risk to develop tuberculosis (TB) due to a higher incidence of TB in remand prison compared to the civil community. They develop TB during incarceration not only due to poor living conditions in remand prison, but also due to some factors affecting their life before imprisonment. Prevention measures against TB spread from penitentiary institutions to society include study of factors, which contribute to TB development. Current study aims at identification of important risk factors of TB development in remand prison in St. Petersburg, Russia. Methods A retrospective matched case–control study was performed from May 2002 to May 2003 in two remand prisons in St. Petersburg. One hundred and fourteen prisoners (57 cases, 57 controls) were interviewed by using standardised questionnaire. Logistic regression analysis was performed to identify risk factors. Results Six factors were significantly linked to the risk of developing TB: narcotic drug use (odds ratio (OR): 2.6, 95% confidence interval (CI): 1.0–6.9), low income (OR: 3.2, CI: 1.2–8.6), high ratio of prisoners per available bed (OR: 4.0, CI: 1.1–15.0), not having own bed clothes (OR: 13.0, CI: 2.7–61.6), and little time outdoors (OR: 3.3, CI: 1.3–8.5). However, good housing before imprisonment (OR: 4.2, CI: 1.1–15.7) was a separate risk factor for TB. Conclusions Three of the risk factors (high number of prisoners per bed, not having own bed clothes, and little time outdoors) are certainly possible to approach by improvement of conditions in remand prisons. The remaining three factors (narcotic drug use, good housing before imprisonment, and low income) provide knowledge about study population, but cannot be intervened by prison’s medical staff.